Effect of concentration of phenolic acid metabolites on TNF-α–stimulated sVCAM-1 protein secretion by HUVECs. PCA (A), PCA3S (B), PCA4S (C), IVA (D), and IVA3G (E) are shown. Data were normalized to a TNF-α control, and columns represent the mean ± SD (n = 3 independent measures). Labeled means without a common letter differ, P ≤ 0.05 (ANOVA with post hoc LSD). *Different from DMSO, P ≤ 0.05 (t test). HUVEC, human umbilical vein endothelial cell; IVA, isovanillic acid; IVA3G, IVA-3-glucuronide; LSD, least square difference; PCA, protocatechuic acid; PCA3S, PCA-3-sulfate; PCA4S, PCA-4-sulfate; sVCAM-1, soluble vascular cellular adhesion molecule 1.